Congestive heart failure (CHF) is a chronic medical condition in which the heart progressively enlarges. The enlarged heart cannot deliver sufficient oxygenated and nutrient rich blood to the body's cells. CHF is commonly associated with left ventricular dysfunction and/or diastolic dysfunction. Left ventricular dysfunction results from impaired emptying of the left ventricular heart chamber. In contrast, diastolic dysfunction refers to alterations in left ventricular properties that adversely affect ventricular filling and diastolic pressure.
A key aspect of normal diastolic filling is the contribution of left ventricular elastic recoil forces to left ventricular filling. Elastic recoil is the ability of the stretched heart to return to its resting position. For example, in a healthy heart, the end-diastolic dimension of the left ventricle may range from 36-56 mm (relaxed) and the end-systolic dimension of the left ventricle may range from 20-40 mm (contracted). A left ventricle in heart failure would typically have larger dimensions than those of a healthy heart. Elastic recoil forces are important in early diastole because they allow rapid and enhanced early filling by assisting the expansion of the left ventricle.
In the case of heart enlargement and/or a decrease in myocardial function, elastic recoil forces may be reduced or absent, thus ceasing to assist early ventricular filling and leading to an increase of the ventricular filling pressure. For example, a patient experiencing CHF typically has an ejection fraction of 40% or less.
Thus, there is a need for a new and useful system, device, and method for treating cardiac dysfunction. This invention provides such a new and useful system, device, and method.